Fenrecz lies directly north of a large delta that eventually turns into a much larger bay. The delta is a mix of swamp and marshland with some large channels/rivers cutting through it. A relatively high treeline and heavy fog impair visibility and the constantly shifting courses and currents of the channels, even the largest ones, make navigating it via boat a tricky endeavor, although one that's attempted on a regular basis as it is still the best way to transport goods to and from Schelotto and other points south.
The most dangerous aspect of the Southern Swamps are the residents, most particularly the warring tribes of lizard men that are the dominant sentient inhabitants. Although many of the tribes have legends of when they fought with strange, demonic-like frog men, those times are well beyond living memory and most of their conflict is with whatever travelers attempt to move through the region or more frequently, with other lizard men.
While the common perception is that lizard men are primitive savages, the majority of them live in massive stone-and-adobe cities built around their many-towered temples (as well as their giant fish-breeding pools) and teeming with slaves captured from the other tribes. Other races are also kept as slaves, although they are not as valuable due to their inability to adapt to the climate and other rigors of the swamps and are therefore much more likely to be used as sacrifices.
There are small amounts of copper deposits in the swamp, meaning that the only metal usually used by lizard men are copper tips to spears and arrows, although some of the higher classes have been known to use metal weapons taken from their victims or forged from other melted-down forms of booty. Armor is typically eschewed or leather/hide, although some lizard men have been seen wearing some kind of fish scale armor, leading to the speculation as to the potential size of the creature these scales were harvested from.
No existing records exist of lizard man engaging in arcane activity as is typically known, with magic being the purview of the shamans and priests. There are several ley lines that criss-cross the swamp, with several of the cities lying close to or on the lines and the various nexuses regarded as especially strange and dangerous places.
Recently reports have become to filter into Fenrecz of lizard man raiding parties deliberately targeting even the large trade convoys and using the resulting captives to fill giant wooden structures that have been erected in the swamp then are then set ablaze, the screams of the captured travelling miles through the swamp air. The import of this increased activity is not yet known, with the main impact being that few captains will risk a swamp crossing without being part of a large and well-protected convoy.
 Mainly because you have to go through extremely rough and dangerous country (scree slopes and active volcanoes) to loop around to the west and eastwards is the Goblin Kingdom. Better to run adrift on a sandbank and fight off any lizard men that might happen by than to experience the depravities of being captured by goblins.
A recent attempt was made by a major merchant captain to establish a caravan route east that would skirt both the edge of the swamp and the extent of the goblin patrols. Several weeks have passed since the initial trailblazing group left Fenrecz and nothing concrete has thus far made it back to the city as to what might have happened.